We often speak of 'astronomically high prices' - 'astronomic' is a common way of describing anything that is extremely large. As a matter of fact, units of measurement are used in the field of astronomy that are far greater than the scale we are used to in everyday life. The nearest star - Proxima Centauri - is around 40,000,000,000,000 kilometres away. This example already shows that the unit of length that we are familiar with, the (kilo-) metre, is completely unsuitable for describing distances in the Universe - but what units are more suitable?Billions and trillions of kilometres are only a stone's throw in space, and these distances would bring us to only a small part of what is, for us, observable space. Therefore, in the field of astronomy special units of length are used, which are intended to make it easier to compare distances in space.

PSR B1620-26 b is an extrasolar planet located approximately 12,400 light-years away, near to the Messier 4 globular cluster in the constellation of Scorpius.The exoplanet has a circumbinary orbit around a pair of stars: a pulsar (PSR B1620-26 A) and a white dwarf (WD B1620-26) with a mass of 0.34 solar masses.The planet (with an unofficial nickname "Methuselah") is the oldest known extrasolar planet, and is believed to be about 12.7 billion years old.

Mt. Cotopaxi at 5,897m in Ecuador; Puncak Jaya, at 4,884m, in the western half of the island of New Guinea and the eastern most province of the Republic of Indonesia and the Rwenzori Mountains that straddle the border between the Democratic Republic of Congo and the Republic of Uganda, currently support the only glaciers on the equator.

However, for a brief moment in time at around 6:12 UT, March 19 2008, a gigantic stellar explosion, called GRB 080319B, reached magnitude 5.8 and became the furthest object visible with the naked eye. GRB 080319B had a red­shift of 0.94 which translates to a distance of 7.5 billion light-years away. The explosions optical afterglow was 2.5 million times more luminous than the most luminous supernova ever recorded.

Gamma-Ray Burst 090423 with a redshift of 8.2 is officially the oldest and most distant known object in the Universe.GRB 090423 exploded about 600 million years after the Big Bang.The object replaces the previous record holder, GRB 080913, with a redshift of 6.7 (placing it 800 million yeas after the big bang).Another distant object, a galaxy called I0K-1 was confirmed spectroscopically with a redshift of 6.964. The galaxy lies so far away that astronomers are seeing it as it appeared 12.88 billion years ago.

The short answer is that we don't know. No one knows if the universe is infinitely large, or if our universe is the only one that exists. But, when we ask this question, we usually mean the size of the observable universe. Through observation, we know that the universe is about 13.7 billion years old, and that space in the universe is expanding; and this expansion has greatly added to the overall width of the Universe (Because space-time is not static, it is a common misconception that the radius of the observable universe must therefore be only 13.7 billion light-years). The edge of the observable universe is now located about 46.5 billion light-years away. The overall diameter of the observable universe is 93 billion light-years across.